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  • Threads on slitting saw arbor

    Having just hacksawed my way through more metal with slightly off square cuts and having to correct this, I am looking at getting an r8 slitting saw arbor. The easiest available saws seem to have a 1" bore and the max size I would be getting would be 5" dia. Some of the arbours have a left hand thread, is this safe?

  • #2
    A 1" arbor will have a key, so it doesn't matter too much which way the bolt goes.

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    • #3
      I have several expensive HSS slitting saws. Rarely use them. Picked up a 2 thin, carbide tipped blades (3 3/4" and a 5" or so I think it was) from the big box store & made 3/4" shank arbors for them. You can run higher feed/speeds with them and they're cheaper to boot.
      Milton

      "Accuracy is the sum total of your compensating mistakes."

      "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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      • #4
        My R8 1" arbor has left-handed threads. I have a nice 6" X 1/8" slitting saw that I use mostly for aluminum. Since the arbor is left-hand thread, I simply turned the saw over and run it in reverse when in use. That way there's little possibility of it loosening, although I run the saw slowly when in use. I really don't know why they made the left hand threads, though. I ordered it from CDCO when I used to buy tools from them and it came that way. The website didn't say what kind of threads.

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        • #5
          I would run slowly, it may actually be a use for the reverse on the mill, it's slowest speed is 120 rpm, so it's not safe for tapping.

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          • #6
            how thick a slitting saw are we talking about?

            Thin large diameter ones can require, well usually do, a VERY slow feed to operate....hacksaw speed even. think a few thou per revolution - and for 5 inch cutter in steel you want 80 rpms. The reason for it being so slow is that inevitably any cutter runs slightly eccentric on an arbor because of clearance between cutting and arbor. So they usually only cut on one part of the revolution. This isn't the case with larger cutters where you can preload the system so they are always cutting...but you'll bust a thin cutter trying to do so. Thin slitting saws also jam up and break (some don't use the key to combat that).

            If I had to I'd be looking for ideas on how to get the cutter running perfectly concentric. Dickeybirds idea might be worth a look, but really, for cut off work, the cheapest smallest bandsaw would be 100 times better and maybe not much more money
            Last edited by Mcgyver; 02-02-2016, 05:14 PM.
            .

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            • #7
              Are we talking jewelers slitting saws or slotting cutters???
              The jewelers saws I have are all 1/2" arbor. The saws have a key slot but the arbor that I use for them doesn't. It has segmented spring loaded rings to accommodate several different hole sizes. Those arbors tighten up under use. One has a 1/2" shank and my other one is R8.
              I also have a set of BP R8 stub arbors 1/2" - 1 1/4" with RH nuts and keys. BP offered them in LH thread at one time. I could never figure out why anyone would want a LH threaded nut arbor?? Like toolguy said if it's keyed it doesn't matter.

              JL.............

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              • #8
                Make one in a lathe like this. Hold the shaft in a collet. The design makes for a nice low profile beyond the blade.



                Using a "key" with slitting saws is not good practice. If they jam there is greater chance of breakage. They do shatter easy. I got a "ding" in my forehead once when one shattered. Now I always use a full face visor when using the saws.

                Cheers,
                Norman

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                • #9
                  Originally posted by Norman Bain View Post
                  Make one in a lathe like this. Hold the shaft in a collet. The design makes for a nice low profile beyond the blade.

                  Using a "key" with slitting saws is not good practice. If they jam there is greater chance of breakage. They do shatter easy. I got a "ding" in my forehead once when one shattered. Now I always use a full face visor when using the saws.

                  Cheers,
                  Norman

                  Hmmm, I've yet to have a problem. I mainly use my slotting saw for aluminum at slow speeds. My Webb mill will go down to 60 rpm. With a 6" diameter saw blade, I'm getting about 95 fpm. I've seen charts that allow much higher speeds than this. Been doing this periodically for 15 years with nary a problem. I use plenty of cutting oil and move in very slowly.

                  My first thought is that, if a key in a saw arbor is bad practice, why do they make them with keys? Inquiring minds want to know. LOL.
                  Last edited by GNM109; 02-03-2016, 03:11 PM.

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                  • #10
                    Originally posted by Norman Bain View Post
                    Make one in a lathe like this...
                    More food for thought on saw arbors from StefanG here:

                    https://www.youtube.com/watch?v=bRQPv4AG2HQ

                    https://www.youtube.com/watch?v=7ejNyQyyR08

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                    • #11
                      If no key, AND with threads that tighten up if the saw slips..... I do not like those. They lead to the &^%$#@! tightest screws in creation, very hard to get unscrewed. The result can be the same as if it DID have a key, because if it tightens up, it will stop spinning just as well as if it had a key, and the jam may still break the blade.

                      I ONCE had a 1/8" saw dent the key, but no other problems of that sort.
                      1601

                      Keep eye on ball.
                      Hashim Khan

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                      • #12
                        I should, in all honesty, qualify my statement about using inexpensive carbide tipped saw blades as slitting saws. All of my usage for these has been in cutting aluminum. They are most likely too aggressive for cutting steel; never tried it myself.
                        Milton

                        "Accuracy is the sum total of your compensating mistakes."

                        "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

                        Comment


                        • #13
                          I have an arbor that I got at Cabin Fever along with some saw blades, and it seems like it would not be able to tighten the nut very much from its cutting action:





                          The blade can also be positioned closer to the shaft, but then there is a lot of metal extending past the cutter:



                          I used it on the lathe, so it was supported on the far end with the live center.

                          http://pauleschoen.com/pix/PM08_P76_P54.png

                          Paul: www.peschoen.com
                          P S Technology, Inc. www.pstech-inc.com
                          and Muttley www.muttleydog.com

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                          • #14
                            Originally posted by Norman Bain View Post
                            Make one in a lathe like this. Hold the shaft in a collet. The design makes for a nice low profile beyond the blade.



                            Using a "key" with slitting saws is not good practice. If they jam there is greater chance of breakage. They do shatter easy. I got a "ding" in my forehead once when one shattered. Now I always use a full face visor when using the saws.

                            Cheers,
                            Norman
                            Not the best arrangement with respect to blade concentricity. You have the issue of concentricity of the blade on the blue insert plus the concentricity of the blue insert in the female recess on the arbor. It would be better if you flipped the male/female sections, with the male section on the arbor.

                            Phil

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                            • #15
                              I have an arbor like Norman's with a 3/4" straight shank. It was fairly expensive and the finish grinding marks are obvious on all important surfaces. The male part is a very close fit in a 1" dia. HSS saw blade hole and also in the female part of the arbor. There is no key. I use it in both directions because about half the time I put the saw on the arbor upside down. No matter, I just flip the mill's reverse switch and proceed. There has never been a time when all the saw teeth were cutting the same amount of metal on each revolution. It doesn't seem to matter as far as blade wear is concerned as I cannot detect any asymmetrical wear on the teeth tips. There has never been an instance of the center bolt getting loose or tighter, but most of the time I am cutting aluminum or soft steel at a leisurely rate with plenty of cutting oil. I have never felt a need to question the set-up or procedure.

                              RWO

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